onsemi MPSA42RLRAG

Overview

MPSA42RLRAG from onsemi is an NPN silicon high-voltage general-purpose transistor in TO-92 package, rated for 300 V_CEO, 500 mA continuous collector current, and 625 mW power dissipation at 25°C ambient. It delivers DC current gain (h_FE) ≥25 at I_C = 1.0 mA and supports switching and linear amplification in high-voltage interface circuits such as telephone line interface cards and flyback converter drivers.

For engineers reviewing the MPSA42RLRAG datasheet, pinout, applications, or equivalent options, key selection criteria include its 300 V_CEO rating, TO-92 leaded package compatibility with through-hole assembly, thermal resistance of 200°C/W (junction-to-ambient), and verified performance across −55°C to +150°C junction temperature range.

Technical Context

The MPSA42RLRAG operates as a discrete NPN bipolar junction transistor optimized for high-voltage switching and amplification where breakdown voltage exceeds 250 V. Its structure supports safe operation up to 300 V_CEO and 300 V_CBO, with base-emitter breakdown limited to 6.0 V and cutoff leakage currents ≤0.1 µA under specified test conditions.

It exhibits f_T = 50 MHz at I_C = 10 mA and V_CE = 20 V, enabling RF-capable signal amplification in low-power HF stages. Collector-base capacitance is 3.0 pF at V_CB = 20 V, supporting fast switching transitions while maintaining stability in high-impedance collector nodes.

Key Specifications

Pinout & Package

Package: TO-92 (Case 29-11), Pb-free, straight-lead configuration per onsemi datasheet MPSA42/D Rev. 8.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-voltage NPN transistor applications.

Compared with BC639 and MPSA92, the MPSA42RLRAG provides unique suitability for 200–300 V switching where NPN sink capability, proven thermal robustness in TO-92, and industry-standard footprint are mandatory - neither alternative offers equivalent voltage-headroom with identical polarity and package form factor.

Availability

MPSA42RLRAG is available at Aetrix Electronics and suitable for telephone line interface cards, flyback converter drivers, relay driver circuits, and high-voltage sensor interfaces requiring stable component supply and long-term manufacturability.

Supply support for MPSA42RLRAG includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The MPSA42RLRAG belongs to onsemi's legacy high-voltage discrete transistor family, designed specifically for cost-sensitive, reliability-critical high-voltage interface and switching functions in analog and mixed-signal systems.

FAQ

What is the maximum collector-emitter voltage rating for MPSA42RLRAG?

The MPSA42RLRAG has a guaranteed minimum collector-emitter breakdown voltage V(BR)_CEO of 300 Vdc at I_C = 1.0 mA and I_B = 0. This rating is validated per onsemi's MPSA42/D datasheet Rev. 8 and defines the absolute upper limit for safe DC or repetitive peak voltage applied between collector and emitter. Exceeding this value risks irreversible avalanche failure. The MPSA42RLRAG must be operated with appropriate safety margins - typically ≤80% of 300 V - in production designs.

Does MPSA42RLRAG have Pb-free construction?

Yes, the MPSA42RLRAG is a Pb-free device compliant with RoHS Directive 2011/65/EU. Its TO-92 package uses lead-free terminations and conforms to onsemi's Pb-free manufacturing standards as documented in the ordering information table on page 3 of the MPSA42/D datasheet. The "G" suffix in related part numbers (e.g., MPSA42G) explicitly denotes Pb-free, and MPSA42RLRAG shares the same qualification and material composition.

What is the thermal resistance junction-to-ambient for MPSA42RLRAG?

The thermal resistance junction-to-ambient (R_JA) for MPSA42RLRAG is 200°C/W under standard JEDEC test conditions (single device on FR-4 board, 1-inch² copper pad). This value assumes no added heatsinking and defines the worst-case temperature rise per watt of dissipated power. At full 625 mW rating, junction temperature will rise ~125°C above ambient - so operation above 25°C ambient requires careful thermal design. The MPSA42RLRAG datasheet confirms this R_JA in the Thermal Characteristics table on page 1.

Can MPSA42RLRAG be used as a direct replacement for MPSA43 in existing designs?

No, the MPSA42RLRAG is not a direct replacement for MPSA43. While both share the same TO-92 package and pinout, the MPSA42RLRAG is rated for 300 V_CEO and 300 V_CBO, whereas the MPSA43 is rated for 200 V_CEO and 200 V_CBO. Substituting MPSA42RLRAG into an MPSA43-design may function electrically but introduces unnecessary voltage overhead and potential parameter mismatch (e.g., h_FE distribution, C_cb). The reverse substitution is unsafe above 200 V. Always verify voltage stress margins before interchanging MPSA42RLRAG and MPSA43.

What is the typical current-gain-bandwidth product (f_T) of MPSA42RLRAG?

The current-gain-bandwidth product (f_T) of MPSA42RLRAG is specified as 50 MHz minimum at I_C = 10 mA, V_CE = 20 V, and f = 100 MHz, per the Small-Signal Characteristics table on page 2 of the MPSA42/D datasheet. This f_T enables usable gain up to ~10–20 MHz in common-emitter amplifier configurations when properly biased and decoupled. The MPSA42RLRAG's f_T is consistent across the MPSA42 family and confirmed by onsemi's characterization data.